Why is it bad to move the pawns in front of the king?

I've read this so many times - after castling, you should never move one of your protective pawns unless you absoloutely have to do so. But why? It seems to me to be rather risky; I have to be extra careful not to get mated on the back-rank, as one rook or queen will do. Having one escape square makes life much easier. At least for 1300 player.

Enlighten me chess gods

Because it will open up your king and it will be unsafe and easier to mate you with the queen for example.

I get that, but not doing so will expose me to an even more dangerous mate attack on the back-rank, if I'm not mistaken...?

Playing black or white is immaterial..I have won against even 100 points

higher rated opponents who opened up their castle without adequate

attacking preparation and mutually supported pieces ..and went for the

pawn pushing without adequate care ..lost against me..

Absolutely. Chess is a game of exceptions ! Moving pawns in front of the king can be good if you can get your punch in first, or if the centre is blocked....but everything is subject to analysis....